B18C7 Running rough, poor fuel consumption

[crobaa]

Hi guys, having a few problems with my b18c7. Took it to my local mechanic today and he ran an ecu scan but came up with nothing. Heres the symptoms


Sometimes a CEL will come on when I hit vtec, it will stay on until car is turned on and off, it doesnt happen often though.

Car has travelled 125km from half a tank (dc2r)

Rough lumpy idle, around 8-900 rpm and can physically feel the motor being lumpy through the pedals.

Possible fuel smell but may just be other traffic, cant be certain

Sometimes I notice a bit of a flat spot in the power band in the mid range

Its important that I mention the motor was running fine, but I replaced alot of parts as a precaution about a month ago, I cant really pinpoint what thing replaced even caused the change, if it all. May just be coincidental.

Car has brand new

Spoon Air Filter
OEM 02 Sensor
OEM Fuel Filter
New Coolant
Penrite Ten Tenths oil 10w-40/hamp oil filter
Stock JDM dc2r exhaust with 100cel cat
IAT sensor
All sensors on T/B
Iridium - BKR7EIX-11 Spark Plugs - These plugs were mentioned to me by the user on here TODA AU, although I noticed they arent listed as suitable for the car in the ngk catalouge, and the car since takes one additional crank to start, but I wouldnt say it has difficulty starting
I have also reset the ecu a few times and ran Liqui Moly injector cleaner through it and also some other brand injector cleaner (not cheapo brand)

It's also worth mentioning than on wide open throttle the car still pulls hard and feels perfect.

[integraR]

are you running aftermarket ecu?

[crobaa]

Nope all stock

[Daveho1]

figure out what that code is first.
then check ignition timing.
and i donno bout those plugs.. id stay with the recomended ones unless the engines been a bit worked

[crobaa]

Yeah that's the plan but I don't know what triggers the cel and I don't really want to drive around on vtec all the time till it comes up

[Daveho1]

well then the next it comes on just pull the code.
also checl that the TPS is calibrated correctly

[Adrian @ SAS]

Test ECT sensor (2 wire - to ecu / single wire sensor is for dash) & replace if faulty
Remove TPS & check correct installation as well as calibration.
(can be installed incorrectly & calibrated at idle correctly but can give over voltage error when installed incorrectly - pin pushed by side of tang rather than between 2 tangs which is correct)

[cbauto]

figure out what that code is first.
then check ignition timing.
and i donno bout those plugs.. id stay with the recomended ones unless the engines been a bit worked

Bkr7eix is the correct plug. Books and manuals recommend platinum plugs.

The above plugs are just the iridium equivalent

[crobaa]

How do I test Ect sensor?

[cbauto]

Manual says you need a scan tool.

Basically its a thermistor.

[Daveho1]

Bkr7eix is the correct plug. Books and manuals recommend platinum plugs.

The above plugs are just the iridium equivalent

aah ok then easy as, i wouldnt know as i just use the coppers. but if they the recomended ones then thats one possability off the list

[Daveho1]

just rip a huge reverse donut then will clear any issues cause instant chicks.

seriously though after thinking a bit i think it would be tps.

[crobaa]

Can tps cause this horrible fuel economy? The most annoying thing is my multimeter is a pro one and doesn't go down to the low voltages used by the tps. It's ironic a $10 one would do the job perfectly.

[cbauto]

just rip a huge reverse donut then will clear any issues cause instant chicks.

seriously though after thinking a bit i think it would be tps.

I would bet ect because he said tps is brand new?

Ect reading wrong causing the ecu to run rich.

[crobaa]

Tps isn't brand new, but tb has been replaced, it was a used one with used sensors all intact

[dorikin]

Did u calibrate it?

[jahniel24]

hmmmm. I would try new spark plug leads!

[cbauto]

hmmmm. I would try new spark plug leads!

Dude. No matter how poor your ignition leads are, thwy would not cause 125 per half tank.

[crobaa]

Nah got a day off tomorrow so will have a crack. Just for reference, does sca/repco sell a multimeter that scales down to those low voltages (for cheap)?

[cbauto]

Just go to local dick smith or jaycar

[Daveho1]

eather way the water temp sensor is under 40 buk from repco at trade price but that sort of ecconomy sounds famillia to me. once with an uncalibrated tps and once with a MAP sensor unpluged (non honda).
so both or none of the sensors mentioned could be to blame

[crobaa]

Ok just pulled off the tps and replaced the original screws with ones I can adjust, I can't help but shake the feeling that the plug part of it was facing the opposite direction prior to taking it off. Is this the correct direction now? I lined up the stick inside in between the metal nibs.

http://i195.photobucket.com/albums/z233/crobaa/834CD0E7-EA71-4EA6-A8E8-E3E6D44EBAB1-23384-00000E9C060512DB_zpsa5e847cb.jpg

[crobaa]

Can't figure out how to face it the opposite direction whilst making sure the stick is in correct position inside :s

[IEVAQ8]

Im pretty sure plug facing down...

[crobaa]

Ok, see in this photo, the two metal bits that the tps stick goes between, are on the intake hose side of the t/b. But on my tb, they are on the manifold side. Is this normal?

http://i195.photobucket.com/albums/z233/crobaa/AD3D3EF5-2302-4350-AD1E-CBED3268E809-23775-00000EDAD7D1A0D8_zpsaeaddcd9.jpg

[Adrian @ SAS]

Sure you didn't get an S2K throttle by mistake?

[crobaa]

Is it exactly the same as stock dc2r except for the tps position? I've put it on with the notches lined up but the plug is facing upwards. Interestingly with the plug facing down I wasn't able to get the correct voltage readings, only with it facing up, readings are perfect now to .01v only time will tell if this has fixed the problem but after a quick drive car does feel better. If this doesn't work I'll have to look into Ect sensor and dizzy.

[Baby Face]

when does the CEL come on?

i would look at a bad o2 sensor.

my b16 ran pretty rough idle with bumpy o2 sensor, the driving slow wasnt very good for it, but full throttle worked as normal, so just when you thought u would push it to show its weakness it didnt use the o2 sensor and used the map sensor readings instead because WOT doesnt care for emissions.

[Daveho1]

so im thinking the upside down tps may be the issue guise

[crobaa]

Closed throttle is .48v and wot is 4.5v. Totally perfect, I've just bled cooling system and reset Ecu. Can somebody tell me what a bog stock b18c7 is supposed to idle at? Just need to adjust the idle screw to get it right

[cbauto]

About 800 to 850

[crobaa]

Really that low? I was thinking more like 1000-1100

[cbauto]

Bog stock?

I have original emissions sticker and it says 800+/- 50
The sticker under the bonnet

[cbauto]

Really that low? I was thinking more like 1000-1100

That's a factor in your poor fuel.

High idle

[crobaa]

Yeah it's interesting because to get the .48v value on closed throttle I had to wind up the grub screw on the throttle stop, might wind it back and settle for a different figure as Honda consider .44-.56 acceptable. Car still throws a cel the instant the car hits vtec, can drive for an hour normally without a cel, then instant I hit vtec it comes on

[crobaa]

Ok finally. Wound down the ct stop screw as low as it will go, recalibrated tps to get the .48v on ct. Tensionsed cable, reset Ecu and the car is idling around 900rpm, is faster and smoother than it's ever been since I've owned it & no more cel!!

Another +1 for the recalibrating tps. Makes a world of difference, car appears to have more torque and is now able to climb a hill in 5th gear at 60km/hr (and my 5th gear has been replaced with a taller one). Can't recommend this enough for all people to do. As far as the tps being upside down, as long as the switch is in line with the tb plate and has a full range of movement it shouldn't be a problem, and the results speak for themselves when driving the car.

[Baby Face]

the most important figure is the idle voltage, full voltage can be played with until it suits you.

[cbauto]

Another happy ending.

Nice.

[crobaa]

Big thanks to everybody for the help

[crobaa]

Ok guys reviving this thread because the CEL is back. Fuel consumption is very good now though, just throws this cel occasionally. The car needs to have been driving for at least 30min in any conditions for the CEL to come on, and usually comes on when vtec is hit. Will turn off as soon as car is off and not come back on again till a long drive. Got it scanned at the mechanic today and he said that its emissions (from the o2 sensor), so its either the o2 sensor itself thats faulty, or something (most likely in the intake according to mechanic) thats causing poor emissions. Seeing as how the o2 sensor has recently been changed and the cel basically came on around that time I'm leaning towards putting another o2 sensor in the car. Just concerned because it was a $160 oem unit from honda. What do you think?

[Baby Face]

try a new map sensor?
when vtec is engaged your engine will ignore the o2 sensors and focus on power instead of emissions and economy.
so the engine will use the map sensor only to determine necessary petrol required.

i would go ahead and change both. from memory all honda MAPs are the same voltage rating but they are mounted different

[crobaa]

Even though I can vtec it all I want until roughly 30min of driving without a cel coming on? Also the car idles perfect, runs perfect, smooth all the way through the power band, even once the cel is on still runs perfect, the only sign the car has an issue is the cel and possibly a poor emissions smell

[Baby Face]

who pulled the code for you and what was the number?

[crobaa]

My local mechanic, can't remember code but it said something along the lines of bad reading from O2 sensor, which apparently means either wrong gasses passing through it or the sensor itself is gone

[crobaa]

The emissions smell may be my imagination, can't say for sure lol

[IEVAQ8]

Go.and re-install ur old o2 sensor....

[crobaa]

Does the mechanic still have it though.. Regardless my new one should come with a warranty. Will suss it out tomorrow

[carayan]

try a new map sensor?
when vtec is engaged your engine will ignore the o2 sensors and focus on power instead of emissions and economy.
so the engine will use the map sensor only to determine necessary petrol required.

i would go ahead and change both. from memory all honda MAPs are the same voltage rating but they are mounted different

http://images.wikia.com/thehungergames/images/f/fd/1346839458-auto-dafuq-dafuq-did-i-just-read-200165.jpeg

[Baby Face]

http://images.wikia.com/thehungergames/images/f/fd/1346839458-auto-dafuq-dafuq-did-i-just-read-200165.jpeg

was my infromation off?
this was what i discovered from trying to find my own CEL's from before.

[Evok]

aftermarket o2 sensors need to be an oem replacement, the length of the wires ( resistance can cause faulty reading ).
but u do get faulty new o2 sensors here and there. just get it replaced and see how it goes.

[crobaa]

Yep mechanic is replacing for me on Monday, brand new oem one from honda, I've got a spare map sensor here so might aswell swap it too, just screw it on or is there a special method like the tps?

[IEVAQ8]

bill...
just change one thing at a time, otherwise ur always chasing ur own tail...
u have a issue and u think its O2, so change that and see how it goes...
if u change O2 and map sensor and the prob is fixed, how the hell will u know which one was faulty...

and PLZ, stop changing shit for the fuk of it...lol
"IF IT AINT BROKE, DONT TOUCH IT"

[crobaa]

I know I know! These were changed a whole ago now lol, but it is good practice to replace O2 sensor

[Super-DA9]

I know I know! These were changed a whole ago now lol, but it is good practice to replace O2 sensor

Not really tbh, an O2 sensor is not a regular maintenance part..

Highly doubtful of it being the MAP sensor as they generally work or they don't. But then again there's always the chance that a sensor has a tiny hairline crack in the circuitry somewhere that expands with heat.

IEVAQ8's advice is spot on. Change the O2, see if it works, if not try other things, but one at a time.

[crobaa]

Not a regular maintenance part, but it is a part that can affect the car adversely but not show any signs, especially with regards to fuel economy. Also my motor is at 170xxx and I don't think it's ever been changed according to receipts that came with it. Will see what happens on Monday. Not changing map sensor at this stage

[Super-DA9]

Sorry it just sounded like by "good practice" you meant replacing it regularly.

[cbauto]

"IF IT AINT BROKE, DONT TOUCH IT"

If it has a spoon equivalent, its worth it.

Even brake fluid.

[mocchi]

didnt u say u just installed new o2 sensor

wat

[crobaa]

Read the whole thread buddy

[mocchi]

Read the whole thread buddy

when i told u abt the o2 senbsor you said no its not it, its brand new

http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

william pls

[cbauto]

when i told u abt the o2 senbsor you said no its not it, its brand new

http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

william pls
http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

[Super-DA9]

when i told u abt the o2 senbsor you said no its not it, its brand new

http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

william pls

http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

http://www.ozhonda.com/forum/customavatars/avatar11984_26.gif

[crobaa]

Regardless of the genuine fault discovered this coming Monday. I will reply in this thread that is it anything other O2 sensor lol

[crobaa]

Yep mocchi you were wrong mate. Poor connection in one of the wires to O2 sensor, not the O2 sensor itself. All good now!

[mocchi]

ok jerod

[PHO]

Yep mocchi you were wrong mate. Poor connection in one of the wires to O2 sensor, not the O2 sensor itself. All good now!

ok oxer

still o2 sensor m8

uacir is right

[u mad?]

mocchi u were wrong mate

[cbauto]

Mocchi auto is Shit

Don't trust

[mocchi]

http://t1.gstatic.com/images?q=tbn:ANd9GcQvlm6fnYEpDNTItNUmly7rBJFQa85bq pGy36qSL2OlNbasWTKZ1g

[crobaa]

Mr tran are you coming to exe on Sunday?

[carayan]

should've checked map sensor
























hueueehheh


at least its all sorted :)

[Super-DA9]

Mocchi you were wrong mate

[TbM]

http://i1352.photobucket.com/albums/q646/tbmindustrys3/dancing_GonnaPotate_zps899e98fa.gif (http://s1352.photobucket.com/user/tbmindustrys3/media/dancing_GonnaPotate_zps899e98fa.gif.html)